@ TFRC: In terms of the Genesis, sample playback is via the YM2612. It is eight bits mono, and the sample rate is up to 44KHz although realistically, I suppose many games used much lower sample rates to save space and computational power, so I guess anything from 11K to 22K should do it.

Most Mega Drive (Genesis) samples seem to be at 16000Hz, although sometimes played at different rates.

If you un-gzip a prepared VGM/VGZ file then you can load it into your favourite wave editor as raw 8-bit PCM and the samples will be neatly segregated near the front of the file (trim off the non-samples around them; raw emulator dumps need to be run through "optvgm" to do the segregation.) Ripped samples might be an interesting base for capturing "the Mega Drive sound".